The present invention relates to a multi-layer flat plate printed circuit antenna, wherein elements of adjacent layers are capacitively coupled to each other. A flat plate receiver is incorporated into and cuts through one or more of the layers, providing a more compact structure and improved sensitivity.
The present invention is another of a progression of inventions on which a number of related, copending applications have been filed. U.S. Pat. No. 4,761,654, Zaghloul, relates to a multi-layer printed circuit antenna employing capacitive coupling among the layers. U.S. Pat. No. 5,005,019, Zaghloul, relates to a printed circuit antenna employing capacitive coupling, wherein radiating elements are slots.
The antennas disclosed and claimed in each of the above-mentioned applications operates in a single sense of polarization, which may be either circular or linear, depending on the configuration of the elements, the elements being fed by respective single feedlines in a power divider network (PDN). U.S. Pat. No. 4,929,959, Sorbello et al., relates to a multi-layer dual-polarization structure, wherein two different orthogonal senses of polarization may be received by a single antenna. The disclosures of all of those copending, commonly assigned applications are incorporated herein by reference.
The antenna disclosed in each of the above-mentioned copending applications, whether implemented in microstrip, stripline, slotline, finline, or coplanar waveguide technologies, requires an amplifier box (a low noise block down-converter, or LNB) which is constructed outside of the antenna structure itself. While this structure works well, it has several deficiencies. First, by requiring coupling of the antenna to an LNB outside of the antenna, there is inherent RF circuit loss. Thus, the receiver has reduced sensitivity. Second, because the receiver box is separate from the antenna, mounting of the overall structure is more difficult and restricted because of its large size.